Plastic packages are popular for storing food products and other items. Recloseable packages that can be securely closed and reopened are particularly popular due to their ability to maintain freshness of the food stored in the package and to minimize leakage to and from the package. Thus, recloseable packages are very common, especially in the food industry. For example, nuts, candy, snacks, cheese, other food, and non-food products can be packed in these packages by form, fill, and seal machines and sold to consumers.
Recloseable packages are typically made to be recloseable via the use of a recloseable feature such as a resealable adhesive seal or a recloseable zipper. Recloseable zippers can be opened and closed either by finger pressure or by use of an auxiliary slider mechanism. Because of the mechanical sealing provided by a zipper, the zipper has become the preferred type of recloseable feature.
Plastic bags with recloseable zippers are commonly formed on vertical and horizontal form, fill, and seal machines. Vertical form, fill, and seal machines typically wrap film around a tube. A vertical seal at the free edges of the web of material is made to develop the tube and a seal at the top or bottom of the tube is made to form a bag. The product is dropped through the tube into the bag. Overwrap form, fill, and seal machines typically wrap film around a product and seal the film to form a bag. Horizontal form, fill, and seal machines generally fold the web and provide two seals that are perpendicular to the fold to create a three-sided package. The product is then placed through the opening in the package and the opening is then sealed.
The recloseable zippers are placed along the web of material at the region that will eventually be the opening of the package. During the form, fill, and seal process, the zipper is usually closed and the two tracks of the zipper are sealed to the web. To form and fill bags with the slider for the zippers requires mounting sliders onto zippers, securing the zippers to bag film, forming a bag from the film, and filling the bag with product. It is desirable to perform all of these steps continuously in order to maximize efficiency and minimize the cost of the bags.